AOAC ERP Gluten Assays - Dec 2018

Annex B

4.1.7.7

Precision of laboratory-internal reproducibility

Table 19 shows the results of an experiment to characterize the laboratory-internal reproducibility (also called intermediate precision). Each sample was extracted six times each by three different persons and tested in three different lots on three different days. The coefficients of variation were between 10.8% and 16% with the lowest value for the snack B sample that was not oat-based but corn-based. Repeatability and reproducibility will be characterized by the accompanying collaborative test. Table 19. Determination of laboratory-internal reproducibility by analysis of three different incurred samples in three different test kit lots by three different persons on three different days; each sample was extract as six-fold replicate.

Snack B

Wheat in Oat

Barley in Oat

41 mg/kg gluten

20 mg/kg

20 mg/kg

replicate

mg/kg gluten

mg/kg gluten

mg/kg gluten

1 2 3 4 5 6

37.3 39.4 37.0 34.4 34.1 33.7 36.0 2.27 34.0 36.4 34.2 32.2 32.9 30.1 33.3 2.11 26.0 29.2 32.4 30.3 28.3 28.7 29.2 2.15 6.3 6.3

17.8 20.4 19.9 17.2 19.9 20.1 19.2 1.37 14.7 16.1 13.4 16.0 22.7 22.1 17.5 3.93 22.4 23.5 20.0 17.0 19.6 21.9 24.5 21.1 2.75 13.1 19.3 3.09 16.0 7.1

21.2 18.0 19.5 20.7 16.0 18.2 18.9 1.92 10.1 20.2 16.0 15.9 14.9 17.1 23.2 17.9 3.21 18.0 16.1 16.3 19.0 18.4 19.0 21.1 18.3 1.87 10.2 18.4 2.31 12.6

Lot 1

Extracts person 1

Day 1

mean

ELISA run person 1

SD

CV [%]

1 2 3 4 5 6

Lot 2

Extracts person 2

Day 2

mean

ELISA run person 2

SD

CV [%]

1 2 3 4 5 6

Lot 3

Extracts person 3

Day 3

mean

ELISA run person 3

SD

CV [%]

7.4

mean

32.8 3.53 10.8

SD

All Lots

CV [%]

Page 31 of 33

RIDASCREEN ® Total Gluten In-house validation report 2018-10-21